System for depositing fibers from a suspension onto a hollow, perforated mold wherein a movable head applies suction from within the mold

ABSTRACT

The present invention relates to a process for depositing a predetermined thickness of fibers upon the surface of a mold comprising, moving a slurry supply container into surrounding relationship with a perforated hollow mold, filling the slurry supply container with a fibrous slurry, moving a suction head into the interior of the hollow mold, pulling a suction through the suction head to cause fibers from the slurry to be deposited on the outside of the mold, moving the suction head so as to pull a suction on an additional area of the mold. A device is provided for carrying out the process comprising a container for holding a fiber suspension therein, a suspension arrangement for holding a hollow mold, cylinders and piston rods for moving the container into surrounding relationship with the hollow mold, a slidably movable suction head extending into the container for insertion into the hollow mold therein, cylinder and sleeve for moving the suction head (and suction pipe connected thereto) in sealing relationship into and out of the interior of the hollow mold for accreting fibers onto the outside surface.

United States Patent 1 1 Rohrer 1451 Feb. 19, 1974 l l SYSTEM FOR DEPOSITING FIBERS FROM A SUSPENSION ONTO A HOLLOW, PERFORATED MOLD WHEREIN A MOVABLE HEAD APPLIES SUCTION FROM WITHIN THE MOLD [76] Inventor: Ernst Rohrer, Ch 9470, Buchs SG,

Switzerland 22 Filed: Jan. 28, 1972 21 Appl. N6; 221,657

52 US. (:1 162/219, 162/228, 162/383, 162/385, 162/389, 264/87 51 Int. Cl. D21j 7/00 [58] Field of Search... 162/219, 228, 387, 388, 389, 162/383, 385, 382, 229; 264/86, 87

[56] References Cited UNITED STATES PATENTS 3,016,090 l/l962 Chaplin 162/385 2,159,638 5/1939 Schur 162/383 X Primary ExaminerRobert L. Lindsay, Jr. Assistant Examiner-Richard I-I. Tushin Attorney, Agent, or FirmLawrence J. Winter I 57 1 ABSTRACT The present invention relates to a process for depositing a predetermined thickness of fibers upon the surface of a mold comprising, moving a slurry supply container into surrounding relationship with a perforated hollow mold, filling the slurry supply container with a fibrous slurry, moving a suction head into the interior of the hollow mold, pulling a suction through the suction head to cause fibers from the slurry to be deposited on the outside of the'mold, moving the suction head so as to pull a suction on an additional area of the mold.

A device is provided for carrying out the process comprising a container for holding a fiber suspension therein, a suspension arrangement for holding a hollow mold,-cylinders and piston rods for moving the container into surrounding relationship with the hollow mold, a slidably movable suction head extending into the container for insertion into the hollow mold therein, cylinder and sleeve for moving the suction head (and suction pipe connected thereto) in sealing relationship into and out of the interior of the hollow mold for accreting fibers onto the outside surface.

10 Claims, 2 Drawing Figures PATENIEB FEB I 91974 FIG.2

FIG.I

SYSTEM FOR DEPOSITING FIBERS FROM A SUSPENSION ONTO A HOLLOW, PERFORATED MOLD WHEREIN A MOVABLE HEAD APPLIES SUCTION FROM WITHIN THE MOLD The present invention relates to a process for the deposition of fibers from a fiber suspension onto the deposition surface of a form which is permeable by liquids, as well as a device to carry out the process.

For the production of most nonwoven intermediate and end products in the garment industry, basically two production processes are used, namely, dry and wet processes.

In the case of the dry process, the fibers are distributed in a stream of air and are deposited on a form. This process is disadvantageous in that the local deposit of the fibers cannot be controlled. Above all, in the case of complicated forms, larger deposits of fibers will develop at certain places than at others and the deposited fiber fleece has undesirable local thickenings. Since it is hardly possible to control the deposit, it is impossible to thicken the deposited fleece at desired places in order to reinforce directly duringthe formation process the garments produced according to the process. Moreover, it is difficult in the case of strengthening of the fleece by means of a binder to apply this binder evenly and in the correct quantities. Additionally, the dry process has the drawback that the work process takes place relatively slowly.

In the case of the wet process and similarly as in the case of processes known from the paper industry, the fibers are deposited in a liquid. The liquid is sucked off through the form developed as a sieve, whereby the fibers are deposited outside the form. Compared to the dry process, the wet process has considerable advantages. Thus, in contrast to the dry process, the binder can be immediately mixed into the suspension, as a result of which a fleece material of good strength with a low requirement for binder can be produced. But, also in the case of the wet process, the problem of an even deposit and control of the deposit exists. In the case of use of smaller flat forms, the known wet process operates quite well, but in the case of large forms great difficulties become apparent, since, in consequence of the difference of the static pressure of the suspension acting upon such large forms, their flow through speed through the form is unequal at various places, which results in an uneven deposit of fibers. Likewise, it is difficult during formation of the fiber fleece to strengthen certain desired parts which, as already mentioned, is desirable above all in the case of the production of articles of clothing. Despite the considerable advantages compared to the dry process, still the wet process up to this time has not succeeded decisively because of the reasons described.

The object of the present invention is the elimination of the disadvantages of the wet process, as explained further above, while retaining the advantages. Therefore, the following object arises, namely, to create a process that will permit control of the local thickness of the fiber deposit.

To achieve this object, a process is proposed which, according to the invention, is characterized in that the individual sections of the form one after the other and for different lengths of time are exposed to apressure drop from the surface of the deposit to the surface of the form which is opposite to said surface of deposit.

The device to carry out the process has been characterized according to the invention by the fact that a suction device has been provided, the suction head of which, having the inlet openings, is guided shiftably along the surface of the form that is opposite the surface of deposit. i

In the following paragraphs an embodiment of the object of the invention is explained in more detail on the basis of the drawing and by way of example. The drawing shows schematically:

FIG. 1 a device for the control of the deposit of fibers on a form prior to the deposition process and FIG. 2 shows the device according to FIG. 1 during the deposition process.

The container, which is open on top and which in the figures is designated by 1, serves for reception of a fiber suspension and is connected with piston rods 2a and 3a of two locally fixed cylinders 2 or 3, which serve for the vertical adjustment of the container. The cylinders 2 and 3 are operated by means of a known control device, not shown. On the bottom of container 1, there is a discharge pipe 4 for the discharge of the container. A control valve 5 inserted into the discharge pipe 4 serves for control of the quantity of the suspension flow off through the discharge pipe 4.

The suction head 8 of the suction device, developed as a round suction plate 6, is disposed in container 1 and the suction pipe 7 is attached to it. Suction plate 6 with its suction opening 6a, being connected with the inside of the pipe, is attached to the suction pipe 7. The suction pipe 7 is guided longitudinally shiftably through the bottom of container 1 and is sealed, with reference to the container, by means of a sealing element 9. A flexible hose 10 is attached to the end of suction pipe 7 which lies outside the'container, of which hose only a part is shown, and said hose is connected with a known suction pump, not shown.

In order to be able to shift the suction head 8 in the longitudinal direction of suction pipe 7, said suction pipe 7 is rigidly coupled with a double acting cylinder 12 via a sleeve 11 encircling said suction pipe, which cylinder guided by. the piston, which is not visible and which is located inside the cylinder, can be moved up and down. The piston subdividing the inside of the cylinderin to two operating chambers is attached by piston rod 13 to the bottom of container 1. Cylinder 12 has two feed pipes 14 and 15, each of which is connected with one of the operating chambers and which pipes are intended for the supply of an operating medium for these operating chambers. The control of the movement of cylinder 12 is accomplished in a known manner by means of conventional control elements that have not been shown.

In addition, a sliding jacket 16, attached to the sleeve 11 of suction pipe 7, encloses a guide rod 17 attached to the bottom of the container with slight play. In the case of shifting the suction head 8, the sliding jacket 16 slides along guide rod 17 which results in the duidance of suction pipe 7.

A rail 18 runs above container 1, on which the sus' pension arrangements 19 carrying the forms 20 are moved. The suspension arrangements 19 can be moved along rail 18 toward container 1 and again away from it.

Form 20, which in the present case serves for the production of trousers, has been developed as a bell shaped hollow form and has an aperture 20a on the bottom. it consists of a finely perforated sheet of metal which, however, at two places designated by 21 has no holes. The thickness of the metal sheet has been so selected that the form can withstand withoutdeformation the mechanical stresses that occur.

A supply tank 22, shown in schematic presentation, serves as a container for the fiber suspension. The supply tank 22 has a discharge pipe 23 in which a lock element 24 has been inserted.

At the beginning of the deposition process, as shown in FIG. 1, an uncoated form 20, mounted in a suspension device 19, is moved into a position above container 1 which is in its terminal position. Cylinder 12 and thus also suction head 8 likewise are in their lower terminal positions.

If form is aligned with suction plate 6 and held in this position, thecontainer 1 is moved into its upper terminal position by operation of cylinders 2 and 3, in

which position said container encloses the form 20 laterally. By supplying the operating medium, via supply pipe 14 and by ventilation via the supply pipe 15, cylinder 12 is moved upwards, as a result of which suction head 8 is shifted in the direction of form 20. Suction plate 6 is pushed through the lower aperture 20a of form 20 into said form and it will fit in a sealing manner against the inside wall of form 20 on the periphery of it.

if suction plate 6 has been completely introduced into form 20 located in container 1, then by opening the closing mechanism 24 in discharge pipe 23 the fiber suspension is moved from the supply tank 22 into container 1. This process of filling will last until, as shown in FIG. 2, form 20 is surrounded by suspension 25.

By switching on the suction pump connected with hose 10, a vacuum is produced in the inside space of form 20 lying above suction plate 6, which causes the fiber suspension to be sucked from the outside toward the form. Since suction plate 6 fits sealingly against form 20, no suspension can be sucked from the underside of the suction plate into the chamber lying above it. The liquid of the suspension on the outside of the form is drawn off through the perforation of form 20 and is carried away through pipe 7 andhose 10. The sucked in fibers on the other hand are deposited on the outside of the part of the form 20 which lies above suction plate 6. Since the places 21 of the form have no holes, no fiber deposit takes place on these places 21.

Suction plate 6 is left in the same position for such a length of time until the fiber layer deposited on the first section of form 20 disposed above suction plate 6 has the desired thickness. When this thickness has been achieved, suction pipe 7 together with suction plate 6 is lowered by a certain predetermined amount by operation of cylinder 12.

The second section of form 20, which just reaches the range of operation of suction head 8, is not yet covered by fibers and the holes of this second section are still open. The flow resistance opposing the sucked in liquid still is slighter in this second section of form 20 which is still open than in the first section of the form which is already covered with fibers. For this reason the liquid principally flows away through the holes of the second section, whereby in the second section a deposit of fibers takes place at the same time.

Whenever the fiber layer deposited in the second section of the form has reached the desired thickness, an

additional lowering of the suction head 8 and a deposition of fibers on the outside of the newly exposed part of the form takes place.

. As described above, suction head 8 is lowered step by step until the entire outside surface of the form is coated with fibers.

After completion of the deposition process, the remaining suspension that still is in container 1 is discharged through discharge pipe 4 and both container 1 and suction head 8 are lowered into their lower terminal positons shown in FIG. 1.

The coated form 20 is shifted to the next following operating station along rail 18 for the purpose of solidification of the deposited fiber fleece, while a new form ready for coating is fed in.

The deposited fiber fleece in correspondence with the step-by-step lowering of the suction head shows zones of varying thickness. At the places 21 of the form where no fibers have been deposited, the fiber fleece having the shape of trousers has openings for the legs, while opening 20a of the form determines the waist opening of the trousers.

The thickness of the layer of fibers deposited on the outside of the form also can be influenced, besides the step-by-step lowering of the suction head as described, by changing the magnitude of the underpressure produced by the suction pump and acting on the inside surface of the form.

The volume of the liquid passing through the form and thus the fiber deposited can be influenced additionally to the above mentioned steps in the process also by the use of a form with holes of different sizes and disposed at locally differeing spacings. If one compares a place with very fine perforations and a place with coarse perforations, then it will turn out that the fine perforations put up a greater resistance to the liquid flowing through the perforations than would be coarser perforations, as a result of which at the place with the fine perforations, per force a lesser fiber deposit will take place.

The preferred flow through of the liquid through the place with the coarser perforations continues for such a length of time until the flow resistance is noticeably increased as a result of the deposited fiber layer.

The fiber deposition on the part of the form lying above suction plate 6 is influenced by the static pressure exerted by the suspension on this part. For the following embodiments, the assumption is made that the above mentioned parameters influencing the deposition remain the same. In the case of a higher level of the suspension, the static pressure exerted by the suspension and thus the speed of flow of the suspension liquid through the holes of the form is greater, which, compared to a lower level, leads to an increased fiber deposition. The level of the suspension can be lowered by the discharge of a part of the suspension through discharge pipe 4, which results in a decreased fiber deposition.

From the above mentioned explanations, it can be gathered that the local thickness of the fiber layer deposited on the form can be controlled by a step-by-step lowering of the suction head with varying lowering speeds, possibly inconnection with a change in the level of the suspension and the underpressure causing the suction, as well as the use of a form having differing porosity as a result of varying perforations.

Instead of a form consisting of a finely perforated metal sheet, a form made of a finely perforated plastic material or a sieve also can be used. The wall thickness of the form must be selected according to the raw material used in such a way that the form can resist any mechanical stresses occurring.

It has turned out to be advantageous to cover the form on its outside or to impregnate it in order to prevent an undesirable adhesion (sticking) of the fibers. Thus, above all, for example, coatings made of polyethylene, polytetrafluoroethylene, polytrifluorochloroethylene, as well as various silicons have proven themselves best.

For shaping the deposited fleece and thus the end product, the outside of the form can be shaped accordingly. As mentioned in the embodiment given by way of example, parts of the surface of the form for example can be made without holes, but it also is possible to provide the form with concave or convex parts, ribs, corrugations, etc.

What is claimed is:

1. A process for depositing a predetermined thickness of fibers upon the surface of a mold comprising, moving a slurry supply container into surrounding relationship with a perforated hollow mold, filling said slurry supply container with a fibrous slurry, moving a suction means into the interior of said hollow mold, pulling a suction through said suction means to cause fibers from the slurry to be deposited on the outside of said mold, moving the suction means so as to pull a suction on an additional area of said mold.

2. The process of claim 1 including the steps of moving said suction means to include additional areas of said hollow mold, and pulling said suctions for different lengths of time.

3. A device for forming a deposit of fibers on a mold comprising container means for holding a fiber suspension therein, holding means for holding a perforated hollow mold, means for moving said container means into surrounding relationship with a hollow mold, a slidably movable suction means extending into said container for insertion into a hollow mold therein, means for moving said suction means in sealing relationship into and out of the interior of said hollow mold for accreting fibers onto the surface of hollow mold.

4. The device of claim 3, wherein said perforated hollow mold has an opening allowing for access to the interior thereof andis held by said holding means, and said suction means is a plate shaped suction head of sufficient dimension to extend into said opening with its periphery in a sealing relationship with the interior surface of said mold. V

5. The device of claim 3, wherein the suction head is provided with a rigid suction pipe guided shiftably through the bottom of the container, and said suction pipe is in communication with said head.

6. The device of claim 5, wherein the suction pipe is provided with ram means attached to the container for slidable movement of said pipe and head longitudinally of said container.

7. The device of claim 6, wherein the container is provided with ram means for vertical movement thereof and said container in its upper most position surrounds within said mold.

8. The device of claim 7, wherein the container has a discharge pipe with a regulating element therein for regulation of the through flow quantity of fiber suspension.

9. The device of claim 8, wherein the mold has areas which are non-porous.

10. The device of claim 9, wherein the deposition surface of the mold is coated with a plastic layer. 

2. The process of claim 1 including the steps of moving said suction means to include additional areas of said hollow mold, and pulling said suctions for different lengths of time.
 3. A device for forming a deposit of fibers on a mold comprising container means for holding a fiber suspension therein, holding means for holding a perforated hollow mold, means for moving said container means into surrounding relationship with a hollow mold, a slidably movable suction means extending into said container for insertion into a hollow mold therein, means for moving said suction means in sealing relationship into and out of the interior of said hollow mold for accreting fibers onto the outside surface of hollow mold.
 4. The device of claim 3, wherein said perforated hollow mold has an opening allowing for access to the interior thereof and is held by said holding means, and said suction means is a plate shaped suction head of sufficient dimension to extend into said opening with its periphery in a sealing relationship with the interior surface of said mold.
 5. The device of claim 3, wherein the suction head is provided with a rigid suction pipe guided shiftably through the bottom of the container, and said suction pipe is in communication with said head.
 6. The device of claim 5, wherein the suction pipe is provided with ram means attached to the container for slidable movement of said pipe and head longitudinally of said container.
 7. The device of claim 6, wherein the container is provided with ram means for vertical movement thereof and said container in its upper most position surrounds within said mold.
 8. The device of claim 7, wherein the container has a discharge pipe with a regulating element therein for regulation of the through flow quantity of fiber suspension.
 9. The device of claim 8, wherein the mold has areas which are non-porous.
 10. The device of claim 9, wherein the deposition surface of the mold is coated with a plastic layer. 